1902 Encyclopedia > Ant > Nervous System of Ants. Role of Instinct.

(Part 5)


(B) Familiar Ants (Formica) (cont.)

Nervous System of Ants. Role of Instinct.

The nervous system of the ants conforms to the ordinary insect type; but in these and other insect forms, we find the highest development of those faculties to which the general name of Instinct is applied. By instinctive acts, in their simplest sense, we mean those acts which an animal performs chiefly from impressions made by surrounding objects upon its nervous or sensory apparatus.

These are very different in character and origin from the actions of the higher vertebrate animals, in which the independent faculty of mind operates as the direct source of action, in place of the surrounding circumstances of the lower form.

Thus, in the case of ants, bees, &c., wonderful as their operations may appear, and regular and methodical as the manner in which they are performed may seem, it will be found that a marked uniformity and likeness of conditions exist, which tend to produce a corresponding similarity of effects. The same external conditions thus tend to induce undeviatingly similar series of phenomena, and under the operation of these acts the animal exercising them may justly be compared to an automatic machine, or to a piece of mechanism, self-directing only in so far as it is directed by external circumstances and outside conditions.

Hence, we find certain species of ants or bees invariably constructing similar series of cells or habitations, and engaging in the same labours as their predecessors, which labours or operations will be faithfully and exactly repeated by succeeding generations. And the automatic and mechanical nature of instinctive acts may be clearly viewed when we contrast them in their essential nature with the directing intelligence and guiding impulse of mind, as we find these qualities exercised in the highest vertebrates.

In the latter case, the mental impulse itself directs alike the physical and psychical operations, and so far from the animal being merely automatic, it assumes the higher phase of nervous action involved in self-originating mental impulse. The actions of the intelligent being are self-determined: those of the instinctive being originate from the outer world. Through the higher nervous centres the intelligent being first appreciates the outward circumstances, and then reacts upon them; the nervous centres of the lower being are, in the first instance, acted upon by the outer world, and then in their turn react upon the organism.

Lastly, and in accordance with the more perfect appreciation of external objects through sensations and perceptions, we have to note in the higher being the operation of the educative power we entitle experience. The ant, or bee, when first introduced into the special sphere of its labours, assumed its functions, and performs its duties as perfectly as if it had been engaged in their performance for a lengthened period. And the long-continued performance of these duties will in no degree tend to make the ant or bee a more perfect or more skillful worker than when the performance of the duties first commenced. Here, again, we observe the operation of the automatic powers; the lower animal, like the perfected machine, operates at once and without any previous experience as perfectly as after a lengthened period of working.

But, in the higher operations directed by intelligence, the being acquires in a gradual manner, and only after a lengthened experience, the perfect manner of working.

In the one case instinct incites the being automatically, or through the excitory outward impressions, to perform the acts; in the other, an intelligent mind first appreciates the impressions, and, through the educative training of experience, is enabled to perform the acts, and to understand in a greater or less degree the reasons which prompt and justify them.

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